Lean FIRE (Financial Independence Retire Early) is the ability to stop working and retire before the average retirement age of over 60+ years of age but retiring on a lower cost of living standard.
When looking at retirement numbers, you need to create a goal to hit for your retirement. You cannot just wait until you are 60+ years old and think you have enough.
Living below your means is about living on less. You do not live paycheck to paycheck anymore. There needs to be a budget, and saving should be an important goal.